Impregnation of fibrous material



May 19, 1964 M. PELLHAMMER IMPREGNATION OF FIBROUS MATERIAL Filed Nov. 30, 1962 INVENTOR. Maurus Pen hammer Attorneys United States, Patent I O 3,133,832 IMPREGNATION F FIBROUS MATERIAL Maurus Pellhammer, Wurttemberg, Germany, assignor to Escher Wyss G.m.b.H., Wurttemberg, Germany, a corporation of Germany Filed Nov. 30, 1962, Ser. No. 241,424 Claims priority, application Germany Dec. 13, 1961 8 Claims. (Cl. 118426) This invention relates to an apparatus for the impregnation of fibrous material in cellulose manufacture, in which the material is placed in a container containing an impregnating liquid, is moved about in the latter by means of a conveying device and after impregnation is lifted out of the container again.

Known impregnating apparatus of this kind operate with conveying devices, such as chains, rakes, and the like, which convey the material to be impregnated through the impregnating liquid. The impregnating liquid at the same time performs a certain circulation in the impregnating vessel, and stationary screens are provided for preventing the material to be impregnated from emerging from the impregnating liquid. These stationary screens, however, become clogged after a short time. This results in considerable differences in the level of the liquid, which is very unfavourable, particularly when the impregnating apparatus is connected to an evacuating arrangement, sealed by liquid columns, since fluctuations in level in the evcuation chamber then interfere with the evacuation process or even render it impossible. Clogging of the screens is particularly prevalent in the case of materials of small particle size, such as straw, bagasse and the like.

It is the object of the invention to prevent the aforesaid disadvantages. In an apparatus for the impregnation of fibrous material of the hereinbefore described kind, for this purpose according to the invention two substantially concentric, at least approximately horizontal cylindrical drums, leaving between each other an annular space, dip into the impregnating liquid in the container. The inner drum is stationary and has in its upper part an outlet for the fibrous material, while the outer drum is rotatable on its axis and has carrier members for the material being impregnated, the rotatable drum at least having screen holes allowing the impregnating liquid to pass through but not the fibrous material. Furthermore, a supply pipe is provided for leading the material to be impregnated into the said annular space left free between the drums, and discharge means are provided for discharging the impregnated material falling through the outlet of the inner stationary drum. I

A constructional example of the subject of the invention is illustrated in simplified manner in the drawing.

FIGURE 1 shows a cross-section'through an impregnating apparatus on the line II in FIGURE 2,

FIGURE 2 shows a section on the line IIII in FIG- URE 1, and

FIGURE 3 shows a portion of FIGURE 1, on a larger scale.

The apparatus shown has a container 1 containing impregnating liquid. Dipping into the liquid in the container 1 are two coaxially mounted cylindrical drums 3 and 4, which have horizontal axes and leave an annular space 2 .free between each other. The inner drum 3 is stationary, is rigidly connected to a cover 5 of the container 1. Its upper part, which extends over a section of its periphery, projects above the liquid level and has an outlet opening 6 for the fibrous material. drum 4 is rotatable on its axis and has carrier members 7 for the material, which project into the annular space 2. Both drums 3 and 4 have screen holes which allow the impregnating liquid to pass through, but not the The outer 3,133,832 Patented May 19, 1964 level.

The fibrous material is led with certainty on a prescribed path through the liquid contained in the impregnating container 1, and the duration of impregnation can be adjusted exactly by regulating the speed of the drum 4. The screen of drum 4, however, during emergence from and immersion into the impregnating liquid, is cleaned from particles of substance which would block the screen orifices. The cleaning effect can be assisted by a spray pipe 10, arranged outside the outer drum 4 above the liquid level. The pipe 10 has holes for directing spray liquid toward the periphery of the outer drum 4. The spray liquid used is impregnating liquid taken from the container 1 by a pipe 11 and put under pressure by a pump 12.

In order also to free the screen holes of the inner stationary drum 3 from clogging particles of material, rows of brushes 13 are mounted on the outer drum so as to brush over the outer periphery of the inner stationary drum 3.

The drum 4 has end rings 14, corresponding to the height of the conveying channel 2, which rings limit the channel in width and also carry the carrier members 7. Like the drums 3, 4, the rings 14 and the carrier members 7 may have screen holes.

The supply pipe 8 leads through an opening 15 of the inner drum 3, which opening lies a certain distance below the level of the liquid 16 in the container 1.

The outer rotatable drum 4 is suspended by means of a pair of belts 17 embracing it and running in annular grooves 18 of the drum 4, from a driving shaft 19, which is mounted over the drums 3 and 4, is provided with pulleys 20 and is driven by a motor 21. A reduction gear 22 is provided between motor 21 and shaft 19. The shaft 19 lies obliquely over the drum axis, so that the drum 4 bears reliably against guide rollers 23 which prevent horizontal displacement of the drum axis.

The container 1 has an overflow 24, which controls the level of impregnating liquid at a predetermined height. The impregnating liquid is supplied by the pipe 8 together with the material to be impregnated and a corresponding quantity of impregnating liquid is removed again from the container 1 by discharge pipes 25.

Without departing from the principle of the invention, the outer rotatable drum 4 may also be mounted in any other manner, for example overhung on a shaft, in which case the inner stationary drum 3 would have to be fixed in overhung fashion to the container wall, or there may be provided in the lower region of the drum 4, on both sides of the drum axis, rollers corresponding to the guide rollers 23, on which rollers the drum 4 rests securely, one of which rollers being driven by a motor.

What is claimed is:

1. An apparatus for impregnating fibrous material with liquid comprising in combination a container for impregnating liquid; means for controlling the liquid level in said containing at a predetermined height; a stationary inner cylindrical drum mounted in said container with at least approximately horizontal axis so as to project with a section of its periphery above said liquid level; an outer cylindrical drum mounted for'rotation coaxially with said inner drum so as to surround said inner drum while leaving between the two an annular space having a section below said liquid level and a section above said liquid level; driving means connected to rotate said outer drum; means for supplying the material to be impregnated to said annular space; and discharge means for the impregnated material arranged below said section of the inner drum which projects above the liquid level; said rotatable outer drum being provided with carrier members projecting into said annular space so as to convey the supplied material through said section of the annular space situated below the liquid level when the outer drum is rotated; and said inner drum, in its section above said discharge means, being provided with an outlet opening through which the impregnated material can fall onto said discharge means; at least the outer drum being provided with screen holes dimensioned to allow the impregnating liquid to pass through but not the fibrous material.

2. The combination defined in claim 1 in which the material supply means comprise a feed pipe passing through the inner drum.

3. The combination defined in claim 2 in which the feed pipe opens into said annular space at a point below the liquid level.

4. The combination defined in claim 1 in which the discharge means comprise a conveyor belt extending below the outlet opening of the inner drum.

5. The combination defined in claim 1 in which for the mounting of the rotatable outer drum a driving shaft having pulleys is arranged above the outer drum, and this outer drum is suspended by means of a pair of driving belts passing over said pulleys and embracing the outer drum, guide rollers being provided laterally of the outer drum.

6. The combination defined in claim 1 in which a spray pipe is arranged outside the outer drum above the liquid level, said pipe having holes for directing spray liquid toward the periphery of the outer drum.

7. The combination defined in claim 6 in which a flow connection including pump means is provided between said spray pipe and a'point of the container situated below the liquid level.

8. The combination defined in claim 1 in which the rotatable outer drum is provided with a brush directed toward the inner drum and in contact with the outer periphery of the inner drum.

References Cited in the file of this patent UNITED STATES PATENTS 1,479,764 Wheeler Jan. I, 1924 

1. AN APPARATUS FOR IMPREGNATING FIBROUS MATERIAL WITH LIQUID COMPRISING IN COMBINATION A CONTAINER FOR IMPREGNATING LIQUID; MEANS FOR CONTROLLING THE LIQUID LEVEL IN SAID CONTAINING AT A PREDETERMINED HEIGHT; A STATIONARY INNER CYLINDRICAL DRUM MOUNTED IN SAID CONTAINER WITH AT LEAST APPROXIMATELY HORIZONTAL AXIS SO AS TO PROJECT WITH A SECTION OF ITS PERIPHERY ABOVE SAID LIQUID LEVEL; AN OUTER CYLINDRICAL DRUM MOUNTED FOR ROTATION COAXIALLY WITH SAID INNER DRUM SO AS TO SURROUND SAID INNER DRUM WHILE LEAVING BETWEEN THE TWO AN ANNULAR SPACE HAVING A SECTION BELOW SAID LIQUID LEVEL AND A SECTION ABOVE SAID LIQUID LEVEL; DRIVING MEANS CONNECTED TO ROTATE SAID OUTER DRUM; MEANS FOR SUPPLYING THE MATERIAL TO BE IMPREGNATED TO SAID ANNULAR SPACE; AND DISCHARGE MEANS FOR THE IMPREGNATED MATERIAL ARRANGED BELOW SAID SECTION OF THE INNER DRUM WHICH PROJECTS ABOVE THE LIQUID LEVEL; SAID ROTATABLE OUTER DRUM BEING PROVIDED WITH CARRIER MEMBERS PROJECTING INTO SAID ANNULAR SPACE SO AS TO CONVEY THE SUPPLIED MATERIAL THROUGH SAID SECTION OF THE ANNULAR SPACE SITUATED BELOW THE LIQUID LEVEL WHEN THE OUTER DRUM IS ROTATED; AND SAID INNER DRUM, IN ITS SECTION ABOVE SAID DISCHARGE MEANS, BEING PROVIDED WITH AN OUTLET OPENING THROUGH WHICH THE IMPREGNATED MATERIAL CAN FALL ONTO SAID DISCHARGE MEANS; AT LEAST THE OUTER DRUM BEING PROVIDED WITH SCREEN HOLES DIMENSIONED TO ALLOW THE IMPREGNATING LIQUID TO PASS THROUGH BUT NOT THE FIBROUS MATERIAL. 